Ava Williams
Anyone who goes swimming with the dog knows that it is better to take a few steps back as soon as your four-legged friend comes out of the water. Because the wet dog has to shake itself dry first. Researchers at the Georgia Institute of Technology have now discovered how important shaking is for animals and how much the shaking frequency varies from animal to animal.
The researchers studied the shaking movements of 17 animal species. From mice to dogs to grizzlies, they measured the height and weight of a total of 33 animals. With a high-speed camera, they recorded the shaking movements of the animals.
They found that the animals had to shake themselves more often the lighter they were.
When dogs shake dry, they move back and forth about eight times per second. Smaller animals, such as mice, shake much faster. A grizzly bear, on the other hand, only shakes four times per second. All of these animals are up to 70 percent dry in just a few seconds after their spin cycle.
Shaking dry saves energy
Over millions of years, animals have perfected their shaking mechanism. Wet fur insulates poorly, the evaporation of trapped water drains energy and the body cools down quickly. “So it’s a matter of life and death to stay as dry as possible in cool weather,” says David Hu, head of the research group.
The fur can also absorb a significant amount of water, making the body heavy. A wet rat, for example, has to carry an additional five percent of its body weight around with it. That’s why animals shake themselves dry so they don’t waste their energy carrying so much extra weight.
Slingshot loose skin
In contrast to humans, animals with fur often have a lot of loose skin, which flaps along with the strong shaking movement and accelerates the movement in the fur. As a result, the animals also dry out faster. If the skin tissue were firm like in humans, it would remain wet, the researchers say.
So if the dog immediately shakes itself off vigorously after the bath and splashes water on everything and everyone in the immediate vicinity, this is not a question of rudeness, but an evolutionary necessity.